Environmental Statement Appendix 6.E (6.3.6.5)
Model Parameters
April 2016
Silvertown Tunnel Appendix 6.E Modelling Parameters Document Reference: 6.3.6.5
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Modelling Parameters
Work element Setting or process used
Model set up
Model used for portal ADMS Roads 4.0.1
Model used for open roads ADMS Roads 4.0.1
Pollutants considered NOx, PM10, PM2.5
Baseline and opening years 2012 and 2021
Met data London City Airport 2012 Surface roughness and minimum Monin-Obukhov length Advice was sought from CERC regarding the surface roughness and minimum Monin-Obukov length parameters across the study area. It was recommended that Surface Roughness should be set at 1 in all models apart from the one which covered the Dartford Crossing where surface roughness would be 0.5. Monin Obukhov length was set at 75m for all of the models.
Air temperature +15C Buildings included No Model receptors All sensitive receptors within 200m, future receptors currently under construction or with full planning permission (not outline)
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Silvertown Tunnel Appendix 6.E Modelling Parameters Document Reference: 6.3.6.5
Receptor height 1.5 Portal represented by Single volume source calculated by ADMS Roads based on portal dimensions Dimensions used for the portal Bore Depth (vertical extent of tunnel)-7.15m N Portal, 7.15m S Portal Outflow Width (width of outflow road) – 9.85n N Portal, 9.85m S Portal
Blackwall Tunnel: Bore Depth (vertical extent of tunnel)-4.7m N Portal, 4.0m S Portal Outflow Width(width of outflow road)-7.1m N Portal, 6.0m S Portal
Portal in cutting No, all at grade Ventilation stack Not yet modelled
Stack parameters (height, temp, velocity, diam) n/a Traffic and emissions Criteria to define ARN DMRB 11.3.1 Silvertown Tunnel Appendix 6.E Modelling Parameters Document Reference: 6.3.6.5
Extent of model A13 between Poplar and the A1153/A123 interchange at Barking. A12 East Cross route between Blackwall Tunnel and the junction with A106 at Hackney Wick. A1261/1203 between Lower Lea Crossing and Aspen Way A1020/A1011 between Silvertown and Beckton A112 south of A13 in Canning Town A102 between Blackwall Tunnel and Kidbrooke A282 Dartford Crossing. Blackwall Tunnel (both directions) Silvertown Tunnel and new supporting infrastructure
Traffic scenario used S142 with off peak split and minor revisions to AADT factoring
Diurnal profile used (e.g. how many hours for AM, IP, PM, OP) Base case, reference case and assessed case; AM (06-09), IP 10-15, PM 16-18, OP1 19-21, OP2 22-06
Method to estimate emissions EFT v6.0.2 with Highways England IAN 185/15 Speed Banding tool. Traffic mix used in EFT (basic/detailed fleet, Inner London, etc) EFT – basic. GIS lookup of roads and London zones (inner/outer/central) applied. Daily average speed or hourly profile? AM, IP, PM, OP1 and OP2 in all scenarios Speed adjustments applied (e.g. exit slips) Speeds banded according to guidance in Highways England IAN 185/15 Gradients considered No Recirculation considered No Processing results
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Silvertown Tunnel Appendix 6.E Modelling Parameters Document Reference: 6.3.6.5
Background values DEFRA maps, in grid motorway, trunk A, and primary A removed. No removal of minor roads in or out of grid sq. No adjustment.
Post processing method and values Abbot NOx to NO2 v4.1 Borough and traffic mix selected according to receptor Verification and adjustment applied? See Appendix 6.B of Environmental Statement Sensitivity tests included? IAN 170/12v3, to adjust modelled results, LTTE6, LAEI projections
Significance determined in accordance with… IAN 174/13